Enhancing PGSQL to be compatible with Informix SQL

I am currently looking into the possibility of extending the current
postgres SQL implementation to be compatible with Informix's SQL
implementation.

The changes required seem relatively straightforward, with one notable
exception.

Requirements:
	1/	Datetime type specifiers (should have no impact)
		o	informix uses datetime specifiers of the form
			DATETIME YEAR TO HOUR.  (which is just the year,
			month, day and hour portion of a datetime).
	2/	Interval type specifiers (ditto)
		o	informix uses interval specifiers of the form
			INTERVAL DAY TO HOUR.  (which is just the 
			day and hour portion of an interval).
	3/	Money type specifiers
		o	informix has money type specifiers that are akin
			to decimal speicifiers
	4/	Informix outer join syntax
		o	informix uses outer joins of the form
			SELECT * FROM a, outer b where a.nr = b.nr
			This will require some post-processing to determine
			the actual join conditions.
	5/	serial data type
		o	Serial type must return inserted key value
		o	Unfortunately (and this is the big bad hit)
			informix's serial datatype does serial number
			generation on a zero inserted valued.
			The modification required to do this may have
			impact on existing programs.


I'd be interested if anyone can see any conceptual difficulties i've
missed in these definitions, and welcome any concepts on the
implementation.


.............................Rod

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| Rod Chamberlin              |  rod@querix.com   Tel +44 1703 232345         |
| Software Engineer           |                   Mob +44 7803 295406         |
| QueriX                      |                   Fax +44 1703 399685         |
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